Aircraft were diverted to nearby Torp airport after two drones began flying near Oslo's main airport at Gardermoen within the space of a few hours, NRK reports.
The first of the two drones caused one of the two runways at Gardemoen to be closed for 20 minutes just before 2:30pm on Wednesday.
Then at 7pm, a second drone caused all incoming flights to be delayed.
Local media Romerikes Blad was first to report on the two drone incidents.
Police said the drones were operated by two different people.
“At 2:20pm we were informed of a drone within the restricted flying zone. It turned out to be an estate agent that wanted to take some pictures of a property,” Police District East commanding officer Terje Marstad told NRK.
The operator will be fined for the infringement, the broadcaster reports.
“Then a 7pm we received a report of a new drone. This time we had to close both runways at Gardermoen,” Marsad said.
The second drone caused prevented aircraft from landing for half an hour. Police do not yet know who was operating it.
The incidents are the second time in two month drones have interfered with flight traffic in Oslo.
READ ALSO: Drone delays traffic at Oslo Airport